Relay



A118- 5,1946- A. J. McMAsTl-:R ET AL l 2,405,319

RELAY Filed March 10, 1943 3 Sheets-Sheet l .f 7 45 @if 37 7E 6+ f5 6@ 66 E5 9 E4 E] 51 ,4 Y jg' 5 47 Pg' 44 47 91 37 45 46 INVENTOR.

7l @new Va/Vwf im.' 75 lari j-60774077) Aug. 6, 1945- A. J. McMAs'rER ET A1. l 2,405,319

RELAY Filed March l0, 1943 3 Sheets-Sheet 2 111./ 11111' llllll'll.'

Aug. 6, 1946. A. J. MoMAs-TER ET AL REL-AY 3 sheet-sheet- 5 INVENToR @710W Ma/172265624 Fl'ed March lO, 1,943

I la zy @556070 Patented Aug. 6, 1946 RELAY Archie J. McMaster, Deerfield, and Larry Jacobson, Chicago, Ill., assignors to G-M Laboratories, Inc., Chicago, Ill., a corporation of Illinois Application March 10, 1943, Serial No. 478,620

(Cl. 20G-8.7)

10 Claims. 1 Our invention relates to electrical relays. The principal object of our invention is the provision of an improved relay.

Another object is the provision of a relay particularly adapted for and meeting the high standard of` performance required in mobile military .equipment such as combat airplane installations and the like, but having features and characteristics which make it particularly desirable for use in the electrical fields generally.

The several unusual features and characteristics of the relay of our invention will be brought out more clearly in the specification which follows.

In the drawings- Fig. 1 is a side elevational view of a relay constructed in accordance with our invention,

Fig. 2 is an elevational view, partly broken away to show construction, looking from the right hand side of Fig. 1,

Fig. 3 is a top plan view of the relay shown in Fig. 1,

Fig. 4 is an irregular bottom plan view looking upwardly along the line 4 4 of Fig. 1,

Fig. 5 is a fragmentary plan sectional view of the movable contact members,

Fig. 6 is a sectional view taken on the Yline 5 6 of Fig. 2 looking in the direction of the arrows,

Fig. is an elevational view, partly in section,

.looking at the left hand side of Fig. 1,

Fig. 8 is an irregular sectional view taken on the line 8-8 of Fig. 7, looking in the direction of the arrows,

Fig. 9 is an irregular sectional view taken on the line 5-9 of Fig. 6 looking in the direction of the arrows,

Fig. 10 is a perspective view showing one of the coils before being mounted in the frame,

Fig. l1 is a plan sectional view taken on the line II-II of Fig. 6, Y

Figs. 12, 13 and 14 are perspective views, respectively, of the relay frame, trunnion bracket and armature,

Fig. 15 is a sectional view of a modified construction, the view being similar t0 Fig. 6 but the embodiment shown having a different arrangement of contacts and terminal lugs, and

Fig. 16 is a fragmentary elevational view looking from the left hand side of Fig. 15.

The relay of our invention, as embodied in the drawings, was primarily designed for the purpose of meeting the severe demands of mobile military equipment. It may take various forms and some of the novel features still maintained, but

2 it is suitably in the general shape of a cube, that is to say, box-like, and has to a pronounced degree the strength and rigidity as well as resistance to vibration and other characteristics of this form of construction.

Among the principal features and advantages of the relay 0f our invention is the ability to seat the armature ush with the core of the coil, regardless of the fact that unfavorable tolerances of assembled parts will pile up in such a way as to require adjustment. The necessary parallelism is obtained without affecting the magnetic eiiiciency of the relay. The parallelism of the armature with the core is maintained, regardless of a pile up of unfavorable tolerances, by adjusting the position of the armature pivot in such a Way as not to affect the path of the magnetic flux as it' passes. through the frame, armature and cores. I'. l

This feature is obtained Without affecting the boX-likeconstruction heretofore referred to, and, in the specific construction shown, by the utilization of a desirable and advantageous construction and relation of relay frame and trunnion l.2:5 bracket, the latter providing the bearing for the ture assembly, sov that even under conditions of severe vibration or rapid acceleration, the susceptibility of the relay. to fail because of lack of balance in any part is greatly reduced. Additional features involve an unusual arrangement of armature restoring spring, and an improved coil and core construction.

Still another feature involves an improved method of and means for adjusting the moving Contact plates, whereby the usual procedure of bending the plates to adjust the contacts is avoided and the loss of Aadjustment due to the tendency of the bent plates to relax is obviated.

'Ihe various features and advantages of our invention will be brought out in connection with the description of the embodiment comprising Figs. 1 to 1 3, inclusive.

The frame 2|, shown in perspective in Fig. 12, braced by a trunnion bracket 22 (Fig. 13), in the manner shown in the several figures, forms the principal support for the relay parts. In addition to comprising a support, the frame 2|, being magnetic, forms a part of the magnetic path in a manner common to relays; but the trunnion bracket 22 is formed of non-magnetic material such as brass.

The trunnion bracket 22 has two generally V- shaped side pieces Z3, each shown with an integral cross bar 24 with openings 26 aligning generally with screw openings 21 in the frame member. The openings 21 may rather snugly receive flat-headed counter-sunk machine screws 28 (see Figs. 6 to 9, inclusive) but the openings 26 are made large enough to permit adjustments for reasons to be pointed out. A clamping bar 29 is threaded to receive the machine screws 26, thus to hold the cross bar 24 of the trunnion bracket in iirm engagement with the associated portion of the frame 2|.

The V-shaped side members 23 of the trunnion bracket have inwardly extending projections 'lying underneath forwardly extending portions 3| of the frame member. Openings 32 in the trunnion bracket align generally with elongated openings 33 in the frame. Twin nuts 34 are rivetedto the trunnion bracket in the manner indicated in Fig. 2, openings 36 (Fig. 13) in the inwardly extending portions of the trunnion bracket receiving the rivets. The twin nuts are threaded to receive machine screws `31 which also extend through upper and lower Contact plates 38 and 3H, respectively, a terminal lug mounting plate 4| (Fig. '8) and insulating baiile plates 42, to thereby .support the stationary contact assembly on the frame. The construction provides for adjustability in `a manner and for a purpose to be pointed out.

An armature 43 (Fig. 14) is pivoted tothe trunnien bracket and, in a usual manner, to be at,- tracted to the pole pieces of a pair of electromagnets 44, some of the features of which will be explained later. The armature is formed of material having suitable magnetic properties and has associated with ita hinge-plate 46, preterably of non-magnetic material, into the ends of which rare fitted trunnon or hinge pins .41, lthe latter adapted to be engaged in openings 48 provided in the trunnion bracket. The hinge-plate 46 lies along a generally, though not quite, rightangular portion 4.9 of the armature and is suitably ,secured thereto. In the draw-ings, we illustrate va Ver-y desirable and simple constructionv wherein yopenings are provided in the angular' portion 49 of the armature and `close, fitting .projections 52 (Fig. '7) formed by hal-f punches in the hinge plate 46 extend into the openings .5| thereby preventing relative movement between' the hinge plate 46 and the armature so long as the parts are held in face-to-face relation. An armature contact bracket 53 is secured to the top face of the angle portion 149 of .the armature, and the hinge plate 46 and armature held in yassembled relation -by means of machine screws 54, which machine screws extend through openings provided in both the armature contact bracket 53 and armature angle portion 49 and .engage in threaded apertures provided in the hinge-plate 46. Y

A restoring spring V56 has one end supported in the frame as shown in Fig. 6 and the other end looped around an annular recess provided near the head of a restoring spring adjusting screw `51 extending through a tail piece 58 on the angular portion 49 of the armature. Adjustment of the screw 51 has very little or no eiect upon the actual tension in the spring 56, but its adjustment changes the point at which the force resulting from the spring tension is applied with respect to the `pivot points of the armature. A stop screw 59 extends through an extending portion .6| of the armature 43 and is adapted to have its head engaged behind a stop portion 62 on the frame 2|. The stop screw 59 is adjustable as appears clear from Fig. 6, and suitable locking means are provided such as the one shown on the drawings involving the utilization of a lock washer and lock nut. A residual shim 63 is secured as by rivets 64 to that face of the armature 43 which is adjacent the pole pieces of the electromagnets d4. This residual shim is formed of suitable non-magnetic material such as nickel silver.

It is understood, of course, that various types of contacts and contact blades may be controlled by Ythe movement of the armature. In Figs. 1 to 13, inclusive, 4.of the drawings, we show a pair of stationary contact members 66 carried by the upper contact plate 38 and a pair of lower contac-ts v61 carried by the lower Contact plate 33. Contact terminals 68 are provided for the upper contacts 66 and contact terminals 69 for the lower contacts 61. The manner in which the contacts and their terminals are constructed and mounted on the upper and lower contact plates appears clear from Fig. 8 and is also brought out in part in the remaining ,iigures Contact blades 1|, in the embodiment shown, comprising part of a U-shaped structure, carry movable contacts 12 disposed between the upper and lower contacts 66 and 61, respectively. Contact blades 1| are mounted on rthe armature contact bracket 53, shims 13 being disposed beneath the contact blades, blade headers 14 being disposed above the contact blades, and lock washer equipped machine screws 16 extending through the entire assembly to maintain the contact blades on the armature contact bracket 53.

The relay coils heretofore referred to as electromagnets 44 comprise cores 11 having heads or flanges 18 and 13, integral with the main shank of the core and having an integral extension 8| extending through and riveted in an aperture provided in the frame as shown in Figure 8. Windings 82 of suitably selected copper wire are protected by insulating headers v83, an insulating core cover 84 ,and an outer suitably designed cover 86, the latter of which may follow conventional practice.

The coils have leads 81 and 88, the former connected and extending through a protecting insulating tube 89 and the latter leading to terminal lugs 9| and y92 ,on the terminal lug mounting plate 4|. Suitable conductors 93 and 64 connect the coils into a controlling .circuit such as in any usual type of electrical equipment in which relays are customarily employed.

Figs. 15 and 16 .show a modification. In this form of the device, the construction is identical with the previously described embodiment except that the iirst described embodiment comprises a two pole relay assembly with the moving poles common and the latter is a three Pole relay containing certain modiiications with respect to the `contacts and terminals only. In Figs. 15 and 16, the parts identical with those in the previous iigures bear identical numerals, but the corresponding parts bear the same numerals as in the iirst described embodiment with the prefix 1 to indicate modiiication. There is a further modification in that the upper contact plate |38 contains a portion |33 extending over to a position above the armature contact bracket |53 and is provided with terminal lugs 56, two of which are in electrical contact with leads |68 running to the coils, and the .remainder of which are connected by means of conductors 91 to lugs 98 forming a continuation of contact blades |1|.

The general manner of producing and assembling the relay of our invention will be apparent from the drawings and the specific description thereof. Some of the novel details of construction will also at once be recognized by those skilled in the art. We invite attention particularly to the unusual compactness, ruggedness and simplicity of design which is made possible by the utilization of the various features, particularly those stressed in the opening paragraphs of the specification. For the assistance of those skilled in the art, however, we wish particularly to point out some of the features which we believe to be particularly desirable and important.

A very important feature of our invention is the accurate location of the armature hinge with respect to the cores of the coils, using features of construction which will assure the manufacturer, independently of the position to which the hinge pins are adjusted, of a uniformly high magnetic efliciency. Using the construction shown in the drawings, the following method of assembly may be used: The twin nuts are riveted to the trunnion bracket; the trunnion bracket is placed in the frame and held loosely in place by the clamping bar and screws 28. The coils are staked in place, and the upper and lower contact plate subassemblies are mounted loosely on the frame by screws 31. The armature is now snapped into place. The relay is then placed in a fixture which properly centers the armature with respect to the frame and the sides of the trunnion bracket are held in their proper positions. A pressure pad presses down on the armature, moving the trunnion bracket to such a, position as to allow the amature to seat flush against both pole faces, or in place of a pressure pad, the coils may be energized during the process of assembling. While the relay is s0 held screws 31 and 54 are tightened. Parallelism will be obtained whether the dimensions of the parts are such as to result in the cores of the coils being relatively too long or too short. Obtaining exact parallelism is favored by using coils whose pole pieces are of substantially identical length, In our method of construction, by an upsetting operation, quite uniform core pieces may be produced, but, if a manufacturing method is used resulting in greater differentiation, pairs of cores may be matched according to length. Thus exact parallelism is obtained; and it will be noted that we employ a residual shim instead of a residual screw. We have found that with good parallelism, wear on the shims is very small.

It will be noted that, by the use of two coils, we provide means for adjusting pivot points of the armature without loss at the air hinge gap, With a two coil construction, there is no air hinge gap loss because the hinge is not in series with the magnetic circuit. Bi-polar relays are known, but, so far as we know, no one has employed a bi-pole relay having the features and advantages which we obtain. Relays with adjustable armature mounting have also been produced but the constructions employed have always been such as to result in relatively high losses at the hinge air gap.

The box-like construction which we employ in our relay possesses very definite advantages, particularly when the relay is employed in unusual locations such as in various positions on mobile military equipment. The usual L or U- shaped relay frames are satisfactory mechanically under normal conditions but under conditions where they are subjected to vibration frequencies such as occur frequently with mobile military equipment, relative movements of the parts of the frames have occurred due to resonance and forced vibrations. We have found that our construction is substantially free of the objection pointed out, and, moreover, the advantages obtained with a minimum amount of weight as contrasted with maximum rigidity. It will be noted that the trunnion bracket is wedged between the legs of the U-shaped frame to form a part of the frame structure proper, with the coils on the web of the U, the armature pivot aligned with one leg of the U, the stationary contact assembly carried by such leg of the U, and the movable contact assembly carried by the armature. The restoring spring is protected but accessible. A practical box results, very rugged and compact, but still capable of many variations in electrical design, as required by different demands of electrical circuits,

Another feature of construction of the embodiments shown is the distribution of the weight of the armature assembly around the axis of rotation in such a way as to approach a condition 0f static balance. This construction also reduces the susceptibility of the relay to fail under conditions of severe vibration, unusual shock due to jolting, rapid acceleration and deceleration, etc.

We call attention to the structure and position of the restoring spring and the manner of adjusting it. It will be noted that the leverage 0f the spring is adjusted by moving one end of it closer to or further away from the axis of rotation of the armature rather than by changing the tension of the spring as in the usual construction. This is important-because the compactness of construction utilized for the purpose of securing other objects of the invention results in placing the spring in a position which Will make it almost inaccessible if another form of adjustment Were employed. It may be noted particularly from Fig. 3 that the head of screw 51 is accessible at a point between the contact blades 1l (looking down from the top of the relay) and the tension is adjusted merely by turning the screw either to the left or right.

Still another important feature of our invention resides in the construction and adjustment of the contact blades. Those skilled in the art will appreciate that the usual procedure would be to bend the blades to properly position the contacts. This method is objectionable principally in the fact that when the spring blades have been bent, a strain is introduced in the metal and this strain tends to be relieved with the result that there is frequently a change in the setting of the blades with the passage of time after the adjustment is made. According to our method, we shim the blades to properly position the contacts. The parts are constructed so that with no shim the movable contacts will engage the stationary contacts 66 with insufficient contact pressure. By placing the proper shims in position, the contact pressure desired may be obtained. We have developed a procedure by which the proper shim can be predicated by a simple preliminary measurement. In actual practice, our method is as follows:

The blades are installed on the relay and the blade mounting screws 16 tightened but without shims 1.5 in position. Without shims it will be recalled that the' contact pressure will be 10W. The relay is then energized. By using a gram gauge applied to the contact end of the blade to measure the force necessary to just close the contacts if they are not closed due to lack of adjustment, or to just open the contacts (as indicated by a pilot light on a xture), the operator can read from a chart the shims required to properly raise the contact blade. From a production engineering standpoint, it is merely necessary to co-relate the force read from the gram gauge with shim thickness which, of course, can also be shown arbitrarily. It is possible to read the shim number directly from the gauge, but, generally speaking, we prefer to furnish a conversion chart to the operator. rIhis operation can be repeated for each pole of the relay and, obviously, the feature can be applied to relays other than the type shown in the drawings. We appreciate that other methods have been employed for adjusting the movable contacts of relays without having to bend the blades, but other methods employed have added greatly to the weight of the relay, have required more space, or possessed some other disadvantage. It will be noted that our construction has all of the advantages of compactness and lightness of weight of a simple form of relay wherein the contact blades are bent, but it has all of the advantages of more elaborate construction in maintaining the condition of the original adjustment.

One of the features of our invention is the core and related construction. It has already been pointed out that the core il is provided with two end flanges 18 and lil. By adopting the construction of the Adouble flange core, we nd it possible to secure the advantages of a relatively smaller diameter core without the attendant disadvantages. The core diameter of the coil designed in accordance with our invention is just large enough to have the maximum iiux density without undue loss of ampere turns because of over-saturation. We are then able to obtain more turns of wire per ohm due to the fact that the average diameter of the turns is reduced because of the small core diameter, and consequently we thereby obtain a greater number of ampere turns per watt. The flange at the heel end, that is to say, where the core is attached to the frame, reduces greatly the reluctance at the air gap between the core and frame. Although the core and fraz'ne are actually in mechanical contact, from a magnetic standpoint the eilect is the same as if there were a break in the solid iron circuit of about .001 inch; and this condition is exaggerated somewhat in usual designs of relays by the fact that the parts are protected by a non-corrosive plating. The reluctance of the circuit at the air gap between the frame and core is generally inversely proportional to the area of the joint, so that increasing the area of the joint by means of the flange, as we do, the ampere turns lost at the junction are reduced markedly. Employing a flange at the armature end of the core permits us to obtain the maximum energy at the air gap and this feature, of course, is important in combination with the high permeance hinge arrangement previously described. We are aware that some of these features have been employed, but so far as we know the various features which we employ have not been used together for the purpose and in such a way as to gain all of the advantage of a high permeance joint between core and frame, an eiliciently small core diameter, a high permeance hinge, and maximum energy at the air gap between the armature and core. It is not essential that all of these features be employed together. We find that we can obtain a very great advantage by using only the feature of the double flanged c-ore. We prefer to produce the vdouble flanged core by an upsetting process because of the fact that the grain direction is then along the core axis and continued into the flange radially, thus further increasing the over-all efficiency of the final relay design. Producing a core of this kind by an uio-setting process also has the advantage of decreased cost as those skilled in the art will understand.

We wish particularly to call attention to the advantages obtainable by the coil-core construction described. By following only the construction of the core such as described, we can greatly increase the efiiciency of any type of relay heretofore produced with the effect that with a given wattage input there is an increase in mechanical output. This results also in a greater safety factor in the form of greater contact pressure, greater wear allowance, permitting a larger air gap, and greater resistance to vibration. It must not be assumed that the core is required to have two substantially symmetrical flanges, although at present, this would appear to be the preferred form. A relatively small core with large integral end extensions capable of fitting into and becoming part of the magnetic path together will function to obtain the marked electromagnetic efficiency to which we have referred.

The advantage of the use of some of the features of our invention is clear from the fact that taking a standard relay we were able, with no major change in design and location of the parts, to increase the mechanical force available at the stall point to about 2.75 times the normal value. This was done with practically n0 increase'in manufacturing cost on a relay which has been substantially a standard piece of equipment for Well over fifteen years.

It will, of course, be understood that the features particularly pointed out and other features and details of construction shown and described may be embodied singly or in combination in other specic designs of relays without departing from the invention as dened in the appended claims.

What we claim as new and desire to protect by Letters Patent of the United States is:

l. In a relay of the character described, a frame member of relatively U shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the said U shaped frame, and an armature pivoted to the trunnion bracket.

2. In a relay of the character described, a frame member of relatively U shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the said U shaped frame, and an armature pivoted to the trunnion bracket, said cores being secured to a web portion of the frame between said legs, and said trunnion bracket being adjustable along the said legs in a direction toward or away from said web, whereby to adjust the parallelism between said armature and faces of the poles of the cores of said coils when the armature is sealed against the pole faces.

3. In a relay of the character described, a frame member of relatively U shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the web portion of said U shaped frame, an armature pivoted to the trunnion bracket, at points substantially aligned with one leg of said U, a stationary contact assembly carried by said last-mentioned leg of the U, and a movable contact assembly carried by the armature, said contact assembly and main portion of the armature being substantially balanced on opposite sides of the axis cf rotation of said armature.

4. In a relay of the character described, a frame member of relatively U shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core within one pole thereof secured to the web portion of said U shaped framed, an armature pivoted to the trunnion bracket, at points substantially aligned with one leg of said U, a stationary contact assembly carried by said last-mentioned leg of the U, and a movable contact assembly carried by the armature, a restoring spring disposed between said coils with one end thereof secured to th'e web of the said U and the other to a tail piece on said armature.

5. In a relay of the character described, a frame member of relatively U shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the web portion of said U shaped frame, an armature pivoted to the trunnion bracket, at points substantially aligned with one leg of said U, a stationary Contact assembly carried by said last mentioned leg of the U, and a movable contact assembly carried by the armature, a restoring spring disposed between said coils with one end thereof secured `to the web of the said U and the other engaging a screw carried by a tail piece of the armature, said screw being accessible for turning whereby to vary the point of engagement of the spring with respect to the pivot point of the armature.

6. In a relay of the character described, a frame member of relatively U shaped cross section formed of materia1 having suitable magnetic properties, a trunnion bracket; formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the web portion of said U shaped frame, an armature pivoted to the trunnion bracket, and a movable contact assembly carried by the armature, the armature and parts carried thereby being so constructed and arranged that the total weight thereof is substantially distributed around the axis of rotation thereof.

7. In a relay of the character described, a frame member of relatively U-shaped cross section formed of material having suitable magnetic properties, a trunnion bracket formed preferably of non-magnetic material wedged between legs of the U to form a box-like frame, a pair of coils having a core with one pole thereof secured to the web portion of said U shaped frame, an armature pivoted to the trunnion bracket, a stationary contact assembly carried by the frame, an armature contact bracket carried by the armature, movable contact carrying blades carried by said armature contact bracket, and shims disposed between said blades and a face of said bracket, the thickness of the shims determining the contact pressure on actuation of the coils, whereby desired contact pressure may be obtained without bending the said blades.

8. In a relay, a frame of material possessing suitable magnetic properties, a coil including a core having integral end flanges, comprising poles of the said core, one of said flanges being in face-to-face contact with the frame, and an armature adapted to engage the other of said flanges as a pole piece in face-to-face relation. the direction of the grain of the metal in said core extending along the core axis and radially in the anges.

9. In a relay, a frame of material possessing suitable magnetic properties, a plurality of coils each including a core having integral end flanges, comprising poles of the said cores, one of said flanges of each core being in face-to-face contact with the frame, an armature adapted to engage the other of said anges of said plurality of said cores as pole pieces in face-to-face relation and a bracket of non-magnetic material carried by the frame, said armature being pivotally mounted on said bracket, and means for adjusting said bracket relative to said frame in a direction parallel to the axes of said coils.

10. In a relay of the character described, a frame formed of suitable magnetic material, at least one coil having a core, one pole of which is free and one pole secured to said frame, an armature pivoted to move into or out of engagement with said free pole, said armature having a tail piece, a screw threaded in said tail piece, and having its axis at an angle to said armature, and a spring tensioned between said screw and frame to draw the armature away from the pole of said coil and core, the construction and arrangement of said spring and screw being such that turning of said screw changes the point of which the force resulting from the spring tension is applied with respect to the pivot point of the armature.

ARCHIE J. MCMASTER.. LARRY JACOBSON. 

